1. Field of the Invention
The invention relates generally to a chill tube for the continuous casting of metals. More specifically, the invention relates to a chill tube whose tube wall has an inner contour in beam blank format, having rounded transitions between the wall sections bordering on one side a flange region and on the other side a crosspiece region, the inner contour being able to be cooled indirectly by a cooling medium supplied from the outside and having cooling channels in the tube wall which extend in its longitudinal direction.
2. Description of Related Art
In the continuous casting of metals, in order to dissipate the heat that accrues, it is known that one may build a chill tube into a water-guiding jacket. In this connection one has to take care that, on account of the inner dimensions of the water-guiding jacket on the one hand, and the outer dimensions of the chill tube on the other hand, a specified gap is formed, from a thermal technology point of view, through which cooling water flows from bottom to top, which absorbs the accruing heat and carries it off. If a chill tube in beam blank shape is installed, the inner contour of the water-guiding jacket has also to correspond to the outer contour of such a shape.
Heat dissipation by the cooling water is largely determined by the speed of the water in the gap between the chill tube and the water-guiding jacket. However, with each recalibration of a chill tube, the gap becomes larger because of the erosion due to wear, and the inevitable reduction in the wall thickness of a chill tube caused thereby. Meanwhile, the enlargement of the water gap is connected with a reduction in the water speed, and consequently also with a reduction in the heat dissipation.
It is known from GB 954 719 that one can furnish chills, for the continuous casting of metals, with cooling bores which extend both in the longitudinal direction and in the transverse direction of the chill tube. However, in the case of chill tubes in beam blank format, the problem arises that the cooling bores transverse to the longitudinal extension can be applied to the chill tubes only with great effort. In addition, in the case of the special geometry of the beam blank format, extreme local heat stresses are created in the transitions between wall sections bordering, on the one side, a flange region and, on the other side, a crosspiece region. In the case of unfavorable geometrical relationships of the transitions, these local heat stresses lead to overheating of the chill tube, and to a drastic reduction in its service life.
It is an object of the invention to provide a chill tube, for the continuous casting of metals, which has an improved service life and in which local overheating is avoided.
These and other objects of the invention are achieved by a chill tube for the continuous casting of metals, whose tube wall (2) has an inner contour (3) in beam blank format, having rounded transitions (6) between the wall sections (9) bordering on one side a flange region (7) and on the other side a crosspiece region (8), the inner contour (3) being able to be cooled indirectly by a cooling medium (cooling water) supplied from the outside; and the cooling channels (4) being provided in the tube wall (2) which extend in its longitudinal direction, wherein the distance (A) between two cooling channels (4) which are adjacent to each other in transitions (6) is smaller than the distance (B) in the remaining wall sections (9).
In another embodiment, the cooling channels (4) are provided only in the rounded transitions (13), while the remaining wall sections (16) as well as the rounded transitions (13) are able to be cooled by a water guiding jacket adapted to the outer contour (17) of the tube wall (18).